How to Add Limestone Veneer to Indoor Walls

Fill a plastic bucket with warm water. Dip a rag or cloth into the bucket and squeeze out as much of the water as possible. Wipe the rag across the indoor wall, removing any dust or debris. Let the wall dry.

Mark the location where you want the veneer on the wall. Draw an outline with a piece of chalk. This step is especially important if you want to apply the veneer only to a portion of the wall.

Mix a 40-pound bag of veneer mortar with 6.25 quarts of water in a plastic bucket. Mix the ingredients with a speed mixer. Wait five minutes and mix again. The mortar should have a thick consistency, similar to mashed potatoes or peanut butter.

Apply a ½-inch layer of veneer mortar onto the wall with a trowel. Start at the top left hand corner and work your way across the wall. Apply the mortar from the left to the right and from the top to the bottom. Wait 20 minutes, and run a notched trowel across the mortar. Move the trowel from left to right. Move the trowel down and move across the wall again. Wait several hours or overnight for the mortar to dry.

Wipe the back of one limestone piece with a damp cloth. Cover the back of one limestone piece with mortar and press against the wall. Apply mortar to the back of each piece and place on the wall, leaving a ½- to 1-inch gap between each stone. Continue applying the stones until you cover the wall or part of the wall.

Run a chisel along the gaps between stones, pulling away any excess mortar. Rub a small broom across the surface of the limestone, brushing off any debris or dust clinging to the surface. Leave the stones in place for 24 hours or until the mortar dries.

Fill a grout bag with fresh mortar. Hold the tip of the bag against the space between stones and squeeze from the top. Move the bag around each stone, filling the gaps between the limestone pieces. Wipe a damp cloth over the stones, removing any mortar clinging to the stones. Once the mortar dries, the veneer is complete.